36.11 Querying Before Exit

When Emacs exits, it terminates all its subprocesses by sending them
the SIGHUP signal. Because subprocesses may be doing
valuable work, Emacs normally asks the user to confirm that it is ok
to terminate them. Each process has a query flag, which, if
non-nil, says that Emacs should ask for confirmation before
exiting and thus killing that process. The default for the query flag
is t, meaning do query.

— Function: process-query-on-exit-flag process

This returns the query flag of process.

— Function: set-process-query-on-exit-flag process flag

This function sets the query flag of process to flag. It
returns flag.

Here is an example of using set-process-query-on-exit-flag on a
shell process to avoid querying: